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Home , Combustor, Frank Whittle, Jet engine, Jet propulsion, Turbofan

Lecture 11.

Turbulent in

X.S. Bai TC in Gas Content

• Development of • Types of gas turbines • Gas turbine cycle • Gas turbine • New gas turbine for clean environment

X.S. Bai TC in Gas Turbines History of gas turbine/jet

Hero of Alexandria, Egypt Chinese solid fuel , 1000 AD 130 BC Leonardo Da ’s chimney jack, 1500

Giovanni Branca, Italy, 1629

Isaac ’s steam wagon, 1687

Johan Barber made first patent, 1791

X.S. Bai TC in Gas Turbines Gas turbine for modern

Frank Whittle, 1930, UK, submitted a patent for a gas turbine for Jets Ltd got contract from Air Minsistry In May 1941, the Whittle W1 engine made its first

X.S. Bai TC in Gas Turbines Gas turbine for modern aviation

Gloster Whittle E28

X.S. Bai TC in Gas Turbines Gas turbine for modern aviation

Hans von Ohain and Max Hahn, 1936, Germany, submitted a patent for a gas turbine for jet propulsion Ernst Company made first true jet propulsion aircraft in 1939, Aug - Sept

Secundo Campiri, Italy, made a gasturbine engine for the CC-2 aircraft, 1940 American (with the help of the British) made W.IX engine in 1941, GE Later Westinghouse Corporation made contiuous development

X.S. Bai TC in Gas Turbines Gas turbine for modern aviation

Ohain

Whittle

X.S. Bai TC in Gas Turbines Rolls-Royce Today

•• aero-engines aero-engines •• marine marine propulsionpropulsion systemssystems •• energy energy businessbusiness •• Annual Annual salessales ofof overover £4.5£4.5 billionbillion •• Orders Orders ofof overover £13£13 billionbillion

X.S. Bai TC in Gas Turbines Newton’s 3rd Law: principle of propulsion

MV

Equilibrium Reaction Action = x (MV)

X.S. Bai TC in Gas Turbines versus Jet Propulsion

Propeller - moves Mvjet LARGE MASS of air at low velocity

Mvaircraft Thrust = M(vaircraft -vjet)

Thrust = m(Vaircraft -Vjet)

Jet - moves small mass of gas at HIGH mVjet mVaircraft VELOCITY

X.S. Bai TC in Gas Turbines Layout

Compressor Combustion Exhaust Chamber Nozzle

mVaircraft mVjet

Shaft Turbine

’Straight-through’ configuration

X.S. Bai TC in Gas Turbines Different Jet Engine Types

CivilCivil turbofanturbofan -- TrentTrent

MilitaryMilitary turbofanturbofan -- EJ200EJ200

X.S. Bai TC in Gas Turbines Reverse Thrust

NetNet 25%25% toto 30%30% thrustthrust

85%85% thrustthrust 15%15% thrustthrust

X.S. Bai TC in Gas Turbines Gas turbine cycle:

40 Pressure (atmospheres) Expansion/ Power 0

1500 Temperature (degrees C)

0 compression combustion exhaust

X.S. Bai TC in Gas Turbines Gas turbine cycle: Brayton cycle

TR: temperature ratio a-b PR: pressure ratio a-b

X.S. Bai TC in Gas Turbines Trend of gas turbine development

X.S. Bai TC in Gas Turbines Gas turbine running conditions

X.S. Bai TC in Gas Turbines Gas turbine combustor

• Stright pipe • Diffuser • Flame stabilization • Optimal air supply

X.S. Bai TC in Gas Turbines Combustor Operation

X.S. Bai TC in Gas Turbines Jet Engine Layout

Can combustor

Whittle W1 engine, 1941

X.S. Bai TC in Gas Turbines Turbulent flame shape and flame height (3) order of estimation

During time Δt, fuel molecule is convected R from inlet to the tip of flame at a speed U, and molecule is by turbulence from air stream to the flame tip u’ at a speed u’. U H H R Δt ∝ ∝ U u' 2R RU R ⇒ H ∝ ∝ u' I I=u’/U: intensity of turbulence

X.S. Bai TC in Gas Turbines Recall: Laminar flame shape and flame height - order of estimation

During time Δt, fuel molecule is convected R from inlet to the tip of flame at a speed U, and oxygen molecule is diffused from air stream to the flame tip. D is diffusion coef.

U H H R2 Δt ∝ ∝ U D

R2U 2R ⇒ H ∝ D

X.S. Bai TC in Gas Turbines Dependence of flame height on injection speed

U

2R

X.S. Bai TC in Gas Turbines Dependence of flame height on burner diameter

H laminar

turbulent U

R

2R

...

X.S. Bai TC in Gas Turbines Jet Engine Layout

Annular cannular

X.S. Bai TC in Gas Turbines Combustor Operation

Primary zone Dilution zone Intermediate zone

Fuel spray nozzle

X.S. Bai TC in Gas Turbines Reverse flow combustor

X.S. Bai TC in Gas Turbines Development of modern gas turbine for clean environment

X.S. Bai TC in Gas Turbines General consideration

100 30 temperature range for 25 80 low emissions 20 60 NOx 15 CO 40 10 , ppmv 20 oxides of nitrogen, ppmv 5

0 0 1600 1700 1800 1900 2000 primary temperature, K

X.S. Bai TC in Gas Turbines Other cocnepts

• Variable geometry • Dry low NOx (DLN) combustion & lean prevaporized premixed (LPP) combustion • Humid air combustion • Rich burner, quick quench, lean burn (RQL) (premixed) • Catalytic combustion • Flameless combustion

X.S. Bai TC in Gas Turbines Diffusion Flames

X.S. Bai TC in Gas Turbines FLOX

X.S. Bai TC in Gas Turbines Flameless: air staged combustion

X.S. Bai TC in Gas Turbines Flames and flameless

flames FLOX

X.S. Bai TC in Gas Turbines Flames and FLOX

X.S. Bai TC in Gas Turbines Flames and flameless

X.S. Bai TC in Gas Turbines